1. Field of the Invention
The present invention relates to a four-stroke engine, and more particularly to a four-stroke engine without a crankshaft and valves which includes a rotatable gas groove and a specific gas feeding and exhausting operation and matches with a rotating arm and a rotary shaft in a driving device and allowing obtaining a rotating speed ration between gear set so as to cycle gas feeding, compression, burst, and gas exhausting.
2. Description of the Prior Art
A cycling operation of a conventional engine has two or four strokes, and a power is supplied to the engine by a crankshaft, i.e., the crankshaft is an output shaft of the engine. However, a top end and a bottom end of the crankshaft can not communicate with each other, so the crank shaft is formed in a curve shape based on a number of the at least one piston so that a vertical movement of a piston is transferred into a rotational movement. But as the at least one piston moves linearly upward and downward, a curved portion of the crank shaft is eccentric, so that the at least one piston moves eccentrically upward and downward, and then the at least one piston produces a lateral force to rub at least one cylinder, thus wearing and breaking the at least one piston and the at least one cylinder.
In addition, the conventional engine is provided with plural gas valve sets so as to operate gas feeding, compression, burst, and gas exhausting, accordingly the engine has a complicated structure.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.